Liquid-sealed vibration-proof device

ABSTRACT

A liquid-sealed vibration-proof device capable of avoiding leakage of liquid upon press fitting of an outer cylinder is provided. An intermediate ring interposed between the outer cylinder and an antivibratory base is formed at its outer circumferential surface with two projecting streaks, the one on liquid chambers side being formed with cutouts. When the outer cylinder is press fitted to an attachment opening of a vehicle body, the liquid confined in a space enclosed between both projecting streaks can escape to the liquid chambers, so that liquid never leaks outside.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to a liquid-sealed type of vibration-proofdevice, for example, for an automobile, to be built in a supportmechanism for a differential, engine, etc., or a part of a suspensionmechanism in order to damp vibrations transmitted to the vehicle bodyside.

[0003] 2. Description of the Related Art

[0004] In an automobile, a liquid-sealed vibration-proof device may be,in general, built in a support mechanism for a differential or engine ora part of a suspension mechanism with the aim of damping vibrationstransmitted to the vehicle body side. One example of such aliquid-sealed vibration-proof device is illustrated in FIG. 18, FIG. 19,FIG. 20 and FIG. 21. FIG. 18 is a perspective view of the liquid-sealedvibration-proof device showing its state before an outer cylinder isfitted.

[0005] This liquid-sealed type of vibration-proof device is providedwith an inner cylinder 101 made of steel, an outer cylinder 102 made ofaluminum disposed outboard in a spaced relation to the inner cylinder101, and an antivibratory base 103 made of rubber-like elastomerinterposed between the inner and outer cylinders 101, 102. The innercylinder 101 is mounted on a diff. case and the outer cylinder 102 ismounted on the vehicle body side, whereby both are connected in avibration-proof manner.

[0006] At an outer circumferential side of the antivibratory base 103there is secured an intermediate cylinder 104 of steel interposedbetween the outer cylinder 102 and the antivibratory base 103. Thisintermediate cylinder 104 includes intermediate rings 105 secured to theantivibratory base 103 in the vicinity of both axial ends thereof and aconnecting element 106 connecting both intermediate rings 105 in itsaxial direction, with the intermediate rings 105 being secured to aninner peripheral surface of the outer cylinder 102, to which theantivibratory base 103 is secured.

[0007] On an outer circumferential surface of the intermediate ring 105two pieces of projecting streaks 107 made of rubber-like elastomer areformed to seal between the outer cylinder 102 and the intermediate ring105 and concurrently to prevent the contact between the both therebyprecluding a corrosion due to any electric potential difference when thedissimilar metals contact with each other.

[0008] Between both intermediate rings 105 at the outer circumferentialside of the antivibratory base 103 there are two spaces 109 divided by apartition wall 108. By reducing the diameter of the outer cylinder 102within a liquid tank and then fixing it to the intermediate rings 105,the spaces 109 are enclosed by the outer cylinder 102 and two liquidchambers 111 mutually communicating through an orifice 110 are thusconstructed.

[0009]FIG. 19 is an enlarged sectional view of the outer cylinder priorto its diameter reducing in the vicinity of the intermediate ring; FIG.20 is an enlarged sectional view of the outer cylinder after thediameter reduction in the vicinity of the intermediate ring; FIG. 21 isan enlarged sectional view of the outer cylinder when press fitted in anopening on the vehicle body side in the vicinity of the intermediatering When the outer cylinder 102 is reduced in diameter within theliquid tank and its inner peripheral surface contacts with both theprojecting streaks 107, a space enclosed by the outer cylinder 102, theintermediate rings 105 and the projecting streaks 107 is shut off fromoutside. A liquid 113 in the space 112 still remains there after thediameter of the outer cylinder 102 has been reduced.

[0010] Since the outer cylinder 102 press fitted in the opening of thebody side member has a reduced diameter when the liquid-sealedvibration-proof device is installed to the vehicle body side, the volumeof the space 112 in which the liquid 113 is sealed is decreased.Therefore there is a danger of part of the liquid 113 leaking throughbetween the projecting streak 107 located on the opposite side to theliquid chamber 111 and the outer cylinder 102 outside.

SUMMARY OF THE INVENTION

[0011] It is an object of this invention to provide a liquid-sealedvibration-proof device capable of preventing leakage of the liquid inpress fitting and fixing its outer cylinder into the opening of anattachment member, accordingly.

[0012] In order to achieve the aforesaid object this invention providesa liquid-sealed vibration-proof device comprising an inner cylinder, anouter cylinder disposed to be spaced apart outwardly from the innercylinder, an intermediate ring interposed between an outercircumferential side of the inner cylinder and an outer circumferentialside of the outer cylinder, wherein a space formed on the outercircumferential side of the antivibratory base at an axially centralside from the intermediate ring is enclosed by the outer cylinder to bemade into a liquid chamber; and the device is characterized in that theouter cylinder and the intermediate ring are made of mutually dissimilarmetals, and two projecting streaks of rubber-like elastomer are formedon an outer circumferential surface of the intermediate ring, with theone projecting streak on the liquid chamber side being formed withcutouts.

[0013] That is to say, the invention is premised on the liquid-sealedvibration-proof device, in which the intermediate ring is interposedbetween the outer circumferential side of the antivibratory base and theinner circumferential side of the outer cylinder so that the outercylinder and the antivibratory base may be fixed by diameter reducing ofthe outer cylinder and press fitting, etc. of the antivibratory baseinto the outer cylinder and two projecting streaks of rubber-likeelastomer are formed on the outer circumferential surface of theintermediate ring to prevent the leakage of liquid out of the liquidchamber and the mutual contact of the outer cylinder and intermediatering of dissimilar metals. In the aforesaid device, of both projectingstreaks, the one projecting streak on the liquid chamber side is formedwith cutouts.

[0014] In this liquid-sealed vibration-proof device, when press fittedand fixed in the opening of an attachment member, the outer cylinder isreduced in diameter whereby the liquid confined in the space enclosed bythe outer cylinder, the intermediate ring and both projecting streaks isdrained out of the space. By forming the cutouts at the projectingstreak on the liquid chamber side, it is possible to escape the confinedliquid to the liquid chamber side so that the liquid may not leakoutside.

[0015] The fixing part of the outer cylinder and the antivibratory baseis not always necessitated to be interposed by the intermediate ring inthe entirety thereof. Of both axially terminal sides of the liquidchamber, the intermediate ring may be interposed at the one side to fixthe outer cylinder and the antivibratory base whereas the outer cylinderand the antivibratory base may be directly bonded together at the otherside. In that case, for example, while compressing the antivibratorybase at its direct bonding side to the outer cylinder, the outercylinder is reduced in diameter in the liquid tank. Otherwise, theantivibratory base is formed so that the intermediate ring may belocated axially outside the outer cylinder and then, in the liquid tank,the intermediate ring is axially forced and press fitted into the outercylinder while deforming the antivibratory base, whereby the liquidchamber is sealed with the liquid.

[0016] Further in the aforementioned liquid-sealed vibration-proofdevice, the invention is characterized in that the intermediate ring issecured to the outer circumferential side of the antivibratory base eachat both axial sides of the liquid chamber, and both intermediate ringsat both axial sides are connected through the connecting element wherebyconstructing an intermediate cylinder interposed between theantivibratory base and the outer cylinder.

[0017] Stated another way, according to the invention, the intermediaterings axially connected through the connecting element are secured atboth axial sides of the liquid chamber to the outer circumferential sideof the antivibratory base. Consequently it is possible to mold theantivibratory base without the outer cylinder and the molding can besimplified. It is also possible to make the distance between the axiallyboth sides of the liquid chamber definite thereby to make the volume ofthe liquid chamber a predetermined size.

[0018] Furthermore the aforesaid liquid-sealed vibration-proof device ischaracterized in that the outer cylinder is made of aluminum and theintermediate ring of steel, which provides a preferred embodiment of theliquid-sealed vibration-proof device of this invention.

[0019] That is, in case where the vehicle body member is made ofaluminum to render the weight of the vehicle body lighter, the outercylinder can be made of aluminum, whereby it is possible to avoid thecorrosion ascribable to any electric potential difference between theouter cylinder and the body side member. On the other hand, theintermediate ring can be made of steel thus making its dimensionssmaller, whereby the device is miniaturized.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The working forms of the liquid-sealed vibration-proof devicepertaining to this invention will be hereinafter described in moredetail in conjunction with the accompanying drawings, in which:

[0021]FIG. 1 is a perspective view of one embodiment of a liquid-sealedvibration-proof device showing the state before attaching of an outercylinder;

[0022]FIG. 2 is a plan view of FIG. 1;

[0023]FIG. 3 is a front elevational view of FIG. 1;

[0024]FIG. 4 is a right-hand side elevation of FIG. 1;

[0025]FIG. 5 is a left-hand side elevation of FIG. 1;

[0026]FIG. 6 is a sectional view of FIG. 3 taken along VI-VI line;

[0027]FIG. 7 is a sectional view of FIG. 2 taken along VII-VII line;

[0028]FIG. 8 is an enlarged sectional view of FIG. 6 showing thevicinity of an intermediate ring;

[0029]FIG. 9 is a sectional view showing a cutout at a projecting streakof the intermediate ring similar to FIG. 8;

[0030]FIG. 10 is a front view of the cutout in FIG. 9;

[0031]FIG. 11 is a front elevation of the device of FIG. 1 afterattaching of the outer cylinder;

[0032]FIG. 12 is a sectional view of FIG. 11 taken along XII -XII line;

[0033]FIG. 13 is a sectional view of FIG. 12 taken along XIII-XIII line;

[0034]FIG. 14 is an axial sectional view of the device showing the stateit is press fitted in the opening of a vehicle body side member;

[0035]FIG. 15 is an enlarged sectional view of another embodiment ofthis invention showing the vicinity of the intermediate ring;

[0036]FIG. 16 is a sectional view similar to FIG. 15 showing a cutout ofits projecting streak in FIG. 15;

[0037]FIG. 17 is a front view showing the cutout in FIG. 16;

[0038]FIG. 18 is a perspective view of a prior art liquid-sealedvibration-proof device showing its state before attaching an outercylinder;

[0039]FIG. 19 is an enlarged sectional view of FIG. 18 showing thevicinity of its intermediate ring before the diameter of the outercylinder is reduced;

[0040]FIG. 20 is an enlarged sectional view similar to FIG. 19 after thediameter reduction of the outer cylinder; and

[0041]FIG. 21 is an enlarged sectional view similar to FIG. 19 showingthe intermediate ring after the outer cylinder is press fitted in theopening of the vehicle body side.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0042] Referring to the embodiment as shown in FIGS. 1 to 14, theliquid-sealed vibration-proof device is provided with an inner cylinder1 made of steel an outer cylinder 2 made of aluminum disposed outwardlyof the inner cylinder to be spaced apart therefrom, and an antivibratorybase 3 made of a rubber-like elastomer. The device is arranged with itsaxial direction oriented in a nearly horizontal direction so that theinner cylinder 1 is attached to a diff. case and the outer cylinder 2 isattached to the vehicle body side, thus connecting both in avibration-proof fashion.

[0043] The innere cylinder 1 is generally cup-shaped with a cylinderpart 4 and a bottom part 5 and is bolt locked to the diff. case bythreading a nut within the cylinder part 4 to a bolt, which is providedon the diff. case so as to project through a bolt hole 6 at the bottompart 5. The outer cylinder 2 is cylinder shaped and press fitted in theopening of the vehicle body side to be fixed.

[0044] The antivibratory base 3 is generally ring shaped, with its upperand lower parts being hollowed out in axially parrallel and mutuallyparallel two planes. The inner peripheral surface of the antivibratorybase 3 is secured to the outer peripheral surface of the inner cylinder1, and on the outer peripheral side of the antivibratory base 3 there issecured an intermediate cylinder 7 made of steel interposed between theouter cylinder 2 and the antivibratory base 3.

[0045] The intermediate cylinder 7 comprises two intermediate rings 8 ofcylindrical form secured in the vicinity of two axial ends of theantivibratory base 3 and two plate-form connecting elements 9 secured tothe outer peripheral surface of the antivibratory base 3 exclusive ofits upper and lower surfaces. The intermediate rings 8 are secured tothe inner peripheral surface of the outer cylinder 2 to connect theinner peripheral surface of the outer cylinder 2 and the antivibratorybase 3 together.

[0046] Each place between upper and lower parts of the antivibratorybase 3 at both axial ends thereof and the intermediate rings 8 is closedby a rubber-like elastomer membrane 10 contiguous to the antivibratorybase 3, and two upper and lower spaces of the antivibratory base 3 areenclosed by the outer cylinder at its outer peripheral side thereby toform liquid chambers 11 a, 11 b sealed with liquid.

[0047] In a clearance 12 between the outer cylinder 2 and the connectingelement 9 bringing both liquid chambers 11 a, 11 b into continuity,partition walls 13 a, 13 b made of rubber-like elastomer are disposed toshut off the liquid chambers 11 a, 11 b. Of these partition walls, theone partition wall 13 a is formed near at its center with an orifice 14,through which to put both liquid chambers 11 a, 11 b into communicationwith each other.

[0048] When the inner and outer cylinders 1, 2 are oscillated verticallyrelatively, the liquid moves through the orifice 14 between the liquidchambers 11 a, 11 b thereby to damp the vibration. Here, upon a highfrequency vibration, the rubber-like elastomer membrane 10 is adapted todeform lest the flow speed of the liquid passing through the orifice 14become too large.

[0049] Within the liquid chambers 11 a, 11 b, a stopper 15 of asynthetic resin secured to the inner cylinder is formed in a protrudingfashion. The stopper 15 is covered with a rubber-like elastomer stopperportion 16 contiguous to the antivibratory base 3 except for its centralvicinity on the outer periphery side. This serves to make the frictionto the liquid large to enhance the damping effect and simultaneouslyserves to inhibit excessive displacement upon vertical vibration byabutting on the outer cylinder 2.

[0050] At both axial ends of the outer circumferential surfaces of theintermediate rings 8 there are formed two projecting streaks 17 a, 17 bso that the outer cylinder 2 and the intermediate rings 8, which are ofdissimilar metals, may not contact with each other. Each the projectingstreak 17 is formed in a manner wrapping over both axial end surfaces ofthe intermediate ring 8 from its inner peripheral surface contiguouslyto the antivibratory base 3 or the rubber-like elastomer membrane 10,and at its outer peripheral surface there is formed a crest portion 18that serves to seal between the outer cylinder 2 and the intermediatering 8.

[0051] Of both projecting streaks 17 a, 17 b, the projecting streak 17 bon the liquid chambers 11 a, 11 b side is formed circumferentiallyequidistantly with four cutouts 19. The cutouts 19 are formed at anaxial edge portion of the intermediate ring 8.

[0052] The manner in which the liquid-sealed type vibration-proof deviceis filled with liquid and installed on the vehicle body side will behereinafter described. First, prior to the fitting of the outer cylinderas shown in FIGS. 1 to 10, the intermediate ring 8 is reduced indiameter, thereby pre-compressing the antivibratory base 3 to enhanceits durability At that time, since the intermediate ring 8 is notcovered at its axial center part with rubber-like elastomer, thediameter reduction work is performed easily.

[0053] The outer cylinder 2 fitting externally on the intermediate ring8 is reduced in diameter within a liquid tank, its both ends are crimpedinwardly and secured to the intermediate ring 8, and then the liquidchambers 11 a, 11 b are filled with liquid. In this state, the liquid isconfined within the space enclosed by the outer cylinder 2, theintermediate ring 8 and both projecting streaks 17 a, 17 b.

[0054] The outer cylinder 2 is press fitted into a collar 20 provided atan opening margin of a frame on the vehicle body side, and theinstallation of the liquid-sealed vibration-proof device to the bodyside is thus completed. At the time of press fitting of the outercylinder 2, the diameter of the outer cylinder 2 is reduced and thevolume of the space enclosed by the outer cylinder 2, intermediate ring8 and both projecting streaks 17 a, 17 b is reduced. The liquid confinedwithin the space at that time flows out of the cutouts 19 of theprojecting streak 17 b into the liquid chambers 11 a, 11 b.

[0055] According to the construction stated above, of the projectingstreaks 17 a, 17 b for avoiding the contact between the outer cylinder 2and the inetrmediate ring 8, the one projecting streak 17 b on theliquid chambers 11 a, 11 b side is formed with the cutouts 19, so thatwhen the outer cylinder 2 is press fitted into the vehicle body side andthe hydraulic pressure between the projecting streaks 17 a, 17 b isincreased, it is possible to escape the liquid toward the liquidchambers 11 a, 11 b so that the liquid may not leak outside. Further,the cutouts 19 are formed at the axial edge portion of the intermediatering 8 and consequently, unless the hydraulic pressure becomes extremelylarge as is the case with the press fitting of the outer cylinder 2, thesealing function is never impaired.

[0056] The invention is not limited to the embodiments described above,but it is possible to vary and modify appropriately the inventionwithout departing from the purview of this invention. For example, avariation as shown in FIG. 15, FIG. 16 and FIG. 17 may be made. That is,the cutouts 19 may be formed at the projecting streak 21 b on the liquidchambers side 11 a, 11 b as is the case with the aforesaid embodiment,and two crests 22 may be formed on the opposite projecting streak 21 ato the liquid chambers 11 a, 11 b without forming any crest on theprojecting streak 21 b, thus making the axial width of the projectingstreak 21 b shorter than that of the projecting streak 21 a, with theresult that the sealing fuction of the projecting streak 21 a is madehigher than that of the projecting streak 21 b.

[0057] By enhancing the sealing fuction of the projecting streak 21 aopposite to the liquid chambers 11 a, 11 b more than that of theprojecting streak 21 b on the liquid chambers 11 a, 11 b, it is possibleto escape the liquid confined between the projecting streaks 21 a, 21 btoward the liquid chambers 11 a, 11 b thereby to avoid more securely theliquid leakage when press fitting the outer cylinder 2 into the vehiclebody side.

[0058] As will be apprent from the description made above, according tothis invention, of the two projecting streaks formed on the outercircumferential surface of the intermediate ring, the one projectingstreak on the liquid chambers side is formed with cutouts and hence uponpress fitting of the outer cylinder into the vehicle body side, theliquid confined between the projecting streaks is escaped to the liquidchambers, so that leakage outside is prevented.

[0059] As a result, in case where the outer cylinder and theintermediate ring are made of dissimilar metals, it is possible topreclude the contact between both without leaking the liquid out, sothat corrosion due to any electric potential difference can beprevented. Therefore it is possible to make the weight of a vehicle bodylighter by making both the outer cylinder and the body side frame ofaluminum and to miniaturize the liquid-sealed vibration-proof device bymaking the intermediate ring of steel.

What is claimed is
 1. A liquid-sealed vibration-proof device comprisingan inner cylinder, an outer cylinder disposed outwardly of the innercylinder to be spaced apart therefrom, an antivibratory base made ofrubber-like elastomer interposed between the inner and outer cylinders,and an intermediate ring interposed between an outer circumferetial sideof the antivibratory base and an inner circumferential side of the outercylinder, a space formed on the outer circumferential side of theantivibratory base at an axially central side from the intermediate ringbeing enclosed by the outer cylinder to be made into liquid chambers,wherein the outer cylinder and the intermediate ring are made ofmutually dissimilar metals and the intermediate ring is formed at itsouter circumferential surface with two projecting streaks, with the oneprojecting streak on the liquid chamber side being formed with cutouts.2. The liquid-sealed vibration-proof device as set forth in claim 1,wherein the intermediate ring is secured to the outer circumferentialside of the antivibratory base at axially both sides of the liquidchambers; the intermediate rings at both sides are interconnectedthrough a connecting element to construct an intermediate cylinderinterposed between the antivibratory base and the outer cylinder.
 3. Theliquid-sealed vibration-proof device as set forth in claim 1, whereinthe outer cylinder is made of aluminum and the intermediate ring is madeof a steel.
 4. The liquid-sealed vibration-proof device as set forth inclaim 2, wherein the outer cylinder is made of aluminum and theintermediate ring is made of a steel.